To provide cellular wireless service, a wireless-service provider typically employs an access network that provides wireless service to one or more access terminals (e.g., cell phones, PDAs, laptops, netbooks, tablets, and/or other wirelessly-equipped devices) in a plurality of service areas. Each such service area may be divided geographically into a number of coverage areas, such as cells and sectors, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS). Within each coverage area, the BTS's RF-radiation pattern may provide one or more wireless links, each on a carrier (or set of carriers), over which access terminals may communicate with the access network. In turn, the access network may provide connectivity with the one or more transport networks, such as the public switched telephone network (PSTN) and/or the Internet.
The wireless links may carry communications between the access network and the access terminals according to any of a variety of wireless protocols. Depending on the protocol employed, each wireless link may also be divided into a plurality of channels for carrying communications between the access network and the access terminals. For example, each wireless link may include a plurality of forward-link channels, such as forward traffic channels and forward paging channels, for carrying communications from the access network to the access terminals. As another example, each wireless link may include a plurality of reverse-link channels, such as reverse traffic channels and reverse access channels, for carrying communications from the access terminals to the access network. Typically, the number of channels on a given wireless link, and thus the number of simultaneous communications the given wireless link can carry, is limited by hardware and/or protocol constraints. As such, an access network may use various techniques to conserve its limited supply of wireless-link channels.
One common way an access network conserves its wireless-link channels is by employing a paging process to locate an idle access terminal before assigning a traffic channel to that access terminal. According to an example paging process, the access network may initiate a sequence of pages of the idle access terminal in the service area in which the access terminal last registered with the access network (i.e., the last-known service area). For instance, the access network may page the idle access terminal a first time in a first set of coverage areas within the last-known service area. If the access network does not receive a page response from the access terminal after a given timeout period (e.g., 10 seconds), the access network may then page the access terminal a second time in a second (typically larger) set of coverage areas within the last-known service area. The access network may continue this process until it receives a page response from the access terminal, until it pages the access terminal in all coverage areas within the last-known service area, and/or until it reaches a time or attempt limit, among other possibilities.